Thymosin Alpha-1 on Juno

Thymosin Alpha-1

Also known as: Tα1, TA1, Zadaxin, Thymalfasin

Approved in 30+ countries for chronic hepatitis B and C and as a sepsis adjunct in critically ill patients — but not in the US. Evidence quality varies sharply by indication, and the popular 'general immune support' framing has no clinical backing.

Reviewed 2026-05-04

What it does

Thymosin Alpha-1 is the synthetic version of a natural peptide originally isolated from the thymus gland. Under the trade names Zadaxin and Thymalfasin, it has been a registered prescription drug in 30+ countries since the 1990s — variously approved for chronic hepatitis B, chronic hepatitis C, as a sepsis adjunct in critically ill patients, and as a vaccine adjuvant in dialysis patients and the elderly. It is not FDA-approved in the United States; here it sits in a gray compounding space. The popular framing as a generic 'immune booster' for healthy adults runs well past where the clinical-trial evidence sits.

Used for

Dose

Starting: 900 mcg · twice weekly
Common: 1,250 mcg · twice weekly
Upper: 1,600 mcg · twice weekly
When: MorningImmunomodulator. Clinic protocols (China hepatitis trials, COVID adjunct studies) administer morning. Daily during cycles, then off.
Site: subcutaneous (chronic hepatitis indications)

Need exact volumes? Open the peptide calculator →

⚠ Caution

Solid organ transplant recipients on immunosuppression (theoretical risk of accelerating rejection; consult transplant team)
Active autoimmune disease (e.g., uncontrolled lupus, severe RA) — immunostimulant could worsen flares
Known hypersensitivity to Tα1 or formulation excipients
Pregnancy and breastfeeding (limited human safety data outside specific trial populations)

Medications & conditions

Thymosin Alpha-1 with immunosuppressant — opposing pharmacologyUser is on immunosuppressive therapy (e.g., post-transplant or autoimmune management). Thymosin Alpha-1 is an immune modulator that enhances T-cell maturation, NK-cell activity, and innate immune signaling — the opposite of what immunosuppressants are prescribed to achieve. Combining the two agents risks undermining the immunosuppressant regimen, potentially triggering graft rejection or autoimmune flare. Do not use without specialist approval.

Often stacked with

LL-37 — Immune modulation + direct antimicrobial; useful in chronic infection or immune-suppression contexts. Inject separately — LL-37 is sensitive to handling.

Your stack

Track this peptide in your protocol — dose, schedule, vials on hand, refill projection. Stays in your browser; no account needed.

Add to my stack

Use this peptide

Featured in protocols

Immune Resilience — Phase 1 — Foundation (TA-1 cycle + glutathione substrate)

Co-injection & overlap

Inject separately (do not co-mix): LL-37

Reconstitution & storage

Lyophilized powder reconstituted with the supplied diluent (typically 1.6 mg vial reconstituted to 1 mL = 1.6 mg/mL). A standard 1.6 mg dose is the full mL. Compounded US-market vials may differ in concentration — verify per batch.

Storage. Lyophilized: refrigerate 2–8 °C per label. Reconstituted: refrigerate; use promptly per vendor expiration (commonly 24 hours for the licensed product, longer for compounded BAC-water reconstitution).

Open the peptide calculator →

Reference

How it works

Modulates T-cell maturation and activity (boosts CD4+ and CD8+ T-cell function), enhances NK cell activity, increases dendritic-cell IL-12 and Th1 cytokine production, and shifts the cytokine milieu toward a Th1-dominant antiviral/antitumor pattern. Acts via TLR-9 and TLR-2 signaling on dendritic cells and through pleiotropic effects on T-cell receptor signaling. Does not directly kill virus or tumor — its effect is to upregulate host immune competence, which is why most evidence comes from contexts of immune compromise (HBV/HCV chronicity, sepsis, chemotherapy).

Juno's take

The editorial gravity here is the jurisdictional split. Thymosin Alpha-1 has decades of approved-market use and solid evidence for specific medical indications — chronic hepatitis, severe sepsis adjunct, certain vaccine adjuvant uses in immunocompromised patients. The 'general immune booster for healthy adults' use you see in US wellness clinics has no controlled-trial support whatsoever. Regulatory approval for one indication doesn't propagate to the others — we hold that line strictly.

EvidenceTier 2 — Human observational

Tiers are per indication. The same molecule can be Tier 1 for one use and Tier 4 for another — the tier reflects published literature, not community framing.

Chronic hepatitis B (in approved markets)

Tier 1high confidence

Multiple controlled trials and meta-analyses (notably across Italian and Chinese cohorts) demonstrate sustained virological response and ALT normalization, sometimes combined with interferon. Approved indication in Italy, China, and other jurisdictions. Tier 1 for THIS specific indication in THESE jurisdictions; tier does not propagate to other claims.

Yang Y et al. 2010 Camerini R et al. 2015

Sepsis adjunct (in critically ill patients)

Tier 2high confidence

ETASS RCT (Wu et al., Crit Care 2013, n=361) and follow-up Chinese trials reported reduced 28-day mortality in severe sepsis. The recent TESTS / ETASS-II readouts have been mixed. Tier 2 because effect size and replication are not yet uniformly positive across populations.

Wu J et al. 2013

Vaccine adjuvant (immunocompromised / dialysis / elderly)

Tier 2medium confidence

Trials in hemodialysis patients receiving hepatitis B vaccine and in elderly receiving influenza vaccine showed improved seroconversion. Modest effect sizes and limited replication in modern settings.

Camerini R et al. 2015

General 'immune support' in healthy adults

Tier 3high confidence

Wellness-clinic and community use is overwhelmingly in healthy adults seeking generic immune optimization or post-COVID recovery. There is no controlled trial of Tα1 in healthy adults for prevention or generic immunity. Mechanism is plausible; the indication-specific evidence is absent.

No primary citations are anchored to this indication — the tier reflects the absence of usable literature, not a missing reference.

Cancer / chemotherapy adjunct